Refactor qt import logic. Fixes #2955
time magic: shorten unnecessary output on windows

On windows the detailed info (i.e. cpu time) is not available and
always reported as zero. The rest of the information is therefore
redundant with the next print (wall time) and can be omitted.
added QT_API_DEFAULT Qt option. Fixed reversed MPL qt logic test.
fix css in .output_area pre

font: inherit conflict with monospace, wich in some cases
leads to non-monospace font (nbviewer for example)
add $include /etc/inputrc to suggested ~/.inputrc

If a user doesn't add this include, their terminal will lose many userfull readline features defined in /etc/inputrc
Merge pull request #2957 from ChrisBeaumont/qt_refactor

Refactor qt import logic.

Closes #2955
Merge pull request #3003 from drevicko/patch-1

add $include /etc/inputrc to suggested ~/.inputrc
Merge pull request #2998 from Carreau/fix-css

fix css in .output_area pre
Merge pull request #2987 from minrk/localfiles

fix local files examples in markdown
Merge pull request #2961 from JanSchulz/shorter_time_magic

%time magic: shorten unnecessary output on windows

On windows the detailed info (i.e. cpu time) is not available and
always reported as zero. The rest of the information is therefore
redundant with the next print (wall time) and can be omitted.
Starting to refactor heart beating of notebook kernels.
More work on the heartbeat.
Made is_alive a method of KernelManager and MultiKernelManager.

It was a property, but it is better suited as a method now.
Added tests in both the KM and MKM case.
Removing last remnant of heartbeat from IOPubHandler.
Removing heartbeat config from the MappingKernelManager.
Adding KerelRestarter.
First go at adding autorestart to MultiKernelManager.
More work on autorestarting.
Adding absolute import to kernelrestarter.
Refactoring kernel restarting.